236 lines
5.8 KiB
C
236 lines
5.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/sysv/ialloc.c
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*
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* minix/bitmap.c
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext/freelists.c
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* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
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*
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* xenix/alloc.c
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* Copyright (C) 1992 Doug Evans
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*
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* coh/alloc.c
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* Copyright (C) 1993 Pascal Haible, Bruno Haible
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*
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* sysv/ialloc.c
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* Copyright (C) 1993 Bruno Haible
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*
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* This file contains code for allocating/freeing inodes.
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*/
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#include <linux/kernel.h>
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#include <linux/stddef.h>
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#include <linux/sched.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/buffer_head.h>
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#include <linux/writeback.h>
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#include "sysv.h"
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/* We don't trust the value of
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sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
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but we nevertheless keep it up to date. */
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/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
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/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
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static inline sysv_ino_t *
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sv_sb_fic_inode(struct super_block * sb, unsigned int i)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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if (sbi->s_bh1 == sbi->s_bh2)
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return &sbi->s_sb_fic_inodes[i];
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else {
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/* 512 byte Xenix FS */
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unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
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if (offset < 512)
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return (sysv_ino_t*)(sbi->s_sbd1 + offset);
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else
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return (sysv_ino_t*)(sbi->s_sbd2 + offset);
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}
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}
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struct sysv_inode *
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sysv_raw_inode(struct super_block *sb, unsigned ino, struct buffer_head **bh)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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struct sysv_inode *res;
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int block = sbi->s_firstinodezone + sbi->s_block_base;
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block += (ino-1) >> sbi->s_inodes_per_block_bits;
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*bh = sb_bread(sb, block);
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if (!*bh)
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return NULL;
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res = (struct sysv_inode *)(*bh)->b_data;
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return res + ((ino-1) & sbi->s_inodes_per_block_1);
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}
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static int refill_free_cache(struct super_block *sb)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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int i = 0, ino;
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ino = SYSV_ROOT_INO+1;
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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode)
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goto out;
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while (ino <= sbi->s_ninodes) {
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if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) {
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*sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino);
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if (i == sbi->s_fic_size)
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break;
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}
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if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
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brelse(bh);
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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode)
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goto out;
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} else
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raw_inode++;
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}
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brelse(bh);
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out:
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return i;
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}
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void sysv_free_inode(struct inode * inode)
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{
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struct super_block *sb = inode->i_sb;
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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unsigned int ino;
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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unsigned count;
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sb = inode->i_sb;
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ino = inode->i_ino;
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if (ino <= SYSV_ROOT_INO || ino > sbi->s_ninodes) {
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printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
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return;
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}
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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode) {
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printk("sysv_free_inode: unable to read inode block on device "
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"%s\n", inode->i_sb->s_id);
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return;
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}
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mutex_lock(&sbi->s_lock);
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count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
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if (count < sbi->s_fic_size) {
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*sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino);
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*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
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}
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fs16_add(sbi, sbi->s_sb_total_free_inodes, 1);
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dirty_sb(sb);
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memset(raw_inode, 0, sizeof(struct sysv_inode));
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mark_buffer_dirty(bh);
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mutex_unlock(&sbi->s_lock);
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brelse(bh);
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}
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struct inode * sysv_new_inode(const struct inode * dir, umode_t mode)
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{
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struct super_block *sb = dir->i_sb;
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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struct inode *inode;
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sysv_ino_t ino;
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unsigned count;
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struct writeback_control wbc = {
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.sync_mode = WB_SYNC_NONE
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};
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inode = new_inode(sb);
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if (!inode)
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return ERR_PTR(-ENOMEM);
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mutex_lock(&sbi->s_lock);
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count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
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if (count == 0 || (*sv_sb_fic_inode(sb,count-1) == 0)) {
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count = refill_free_cache(sb);
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if (count == 0) {
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iput(inode);
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mutex_unlock(&sbi->s_lock);
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return ERR_PTR(-ENOSPC);
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}
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}
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/* Now count > 0. */
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ino = *sv_sb_fic_inode(sb,--count);
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*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
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fs16_add(sbi, sbi->s_sb_total_free_inodes, -1);
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dirty_sb(sb);
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inode_init_owner(&init_user_ns, inode, dir, mode);
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inode->i_ino = fs16_to_cpu(sbi, ino);
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inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
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inode->i_blocks = 0;
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memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data));
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SYSV_I(inode)->i_dir_start_lookup = 0;
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insert_inode_hash(inode);
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mark_inode_dirty(inode);
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sysv_write_inode(inode, &wbc); /* ensure inode not allocated again */
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mark_inode_dirty(inode); /* cleared by sysv_write_inode() */
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/* That's it. */
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mutex_unlock(&sbi->s_lock);
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return inode;
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}
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unsigned long sysv_count_free_inodes(struct super_block * sb)
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{
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struct sysv_sb_info *sbi = SYSV_SB(sb);
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struct buffer_head * bh;
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struct sysv_inode * raw_inode;
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int ino, count, sb_count;
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mutex_lock(&sbi->s_lock);
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sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes);
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if (0)
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goto trust_sb;
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/* this causes a lot of disk traffic ... */
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count = 0;
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ino = SYSV_ROOT_INO+1;
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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode)
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goto Eio;
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while (ino <= sbi->s_ninodes) {
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if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
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count++;
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if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
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brelse(bh);
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raw_inode = sysv_raw_inode(sb, ino, &bh);
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if (!raw_inode)
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goto Eio;
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} else
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raw_inode++;
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}
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brelse(bh);
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if (count != sb_count)
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goto Einval;
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out:
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mutex_unlock(&sbi->s_lock);
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return count;
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Einval:
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printk("sysv_count_free_inodes: "
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"free inode count was %d, correcting to %d\n",
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sb_count, count);
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if (!sb_rdonly(sb)) {
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*sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count);
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dirty_sb(sb);
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}
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goto out;
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Eio:
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printk("sysv_count_free_inodes: unable to read inode table\n");
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trust_sb:
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count = sb_count;
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goto out;
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}
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